Metabolomic screening of radioiodine refractory thyroid cancer patients and the underlying chemical mechanism of iodine resistance.

Radioiodine refractory (RAIR) patients do not benefit from iodine-131 therapy. Thus, timely identification of RAIR patients is critical for avoiding ineffective radioactive iodine therapy. In addition, determining the causes of iodine resistance will facilitate the development of novel treatment strategies. This study was comprised of 20 RAIR and 14 non-radioiodine refractory (non-RAIR) thyroid cancer patients. Liquid chromatography-mass spectrometry was used to identify differences in the serum metabolites of RAIR and non-RAIR patients. In addition, chemical assays were performed to determine the effects of the differential metabolites on iodine uptake. Metabolic pathway enrichment analysis of the differential metabolites revealed significant differences in the phenylalanine and tyrosine metabolic pathways. Notably, quinate and shikimic acid, metabolites of the tyrosine pathway, were significantly increased in the RAIR group. In contrast, the phenylalanine pathway metabolites, hippuric acid and 2-phenylacetamide, were markedly decreased in the RAIR group. Thyroid peroxidase plays an important role in catalyzing the iodination of tyrosine residues, while the ionic state of iodine promotes the iodination reaction. Quinate, shikimic acid, hippuric acid, and 2-phenylacetamide were found to be involved in the iodination of tyrosine, which is a key step in thyroid hormone synthesis. Specifically, quinate and shikimic acid were found to inhibit iodination, while hippuric acid and 2-phenylacetamide promoted iodination. Abnormalities in phenylalanine and tyrosine metabolic pathways are closely associated with iodine resistance. Tyrosine is required for thyroid hormone synthesis and could be a potential cause of iodine resistance.

CLIP170 inhibits the metastasis and EMT of papillary thyroid cancer through the TGF-ß pathway.

Metastasis poses a significant challenge in combating tumors. Even in papillary thyroid cancer (PTC), which typically exhibits a favorable prognosis, high recurrence rates are attributed to metastasis. Cytoplasmic linker protein 170 (CLIP170) functions as a classical microtubule plus-end tracking protein (+TIP) and has shown close association with cell migration. Nevertheless, the specific impact of CLIP170 on PTC cells remains to be elucidated. Our analysis of the GEO and TCGA databases unveiled an association between CLIP170 and the progression of PTC. To explore the impact of CLIP170 on PTC cells, we conducted various assays. We evaluated its effects through CCK-8, wound healing assay, and transwell assay after knocking down CLIP170. Additionally, the influence of CLIP170 on the cellular actin structure was examined via immunofluorescence; we further investigated the molecular expressions of epithelial-mesenchymal transition (EMT) and the transforming growth factor-ß (TGF-ß) signaling pathways through Western blotting and RT-qPCR. These findings were substantiated through an in vivo nude mouse model of lung metastasis. We observed a decreased expression of CLIP170 in PTC in contrast to normal thyroid tissue. Functionally, the knockdown of CLIP170 (CLIP170KD) notably enhanced the metastatic potential and EMT of PTC cells, both in vitro and in vivo. Mechanistically, CLIP170KD triggered the activation of the TGF-ß pathway, subsequently promoting tumor cell migration, invasion, and EMT. Remarkably, the TGF-ß inhibitor LY2157299 effectively countered TGF-ß activity and significantly reversed tumor metastasis and EMT induced by CLIP170 knockdown. In summary, these findings collectively propose CLIP170 as a promising therapeutic target to mitigate metastatic tendencies in PTC.

LINC00887 Acts as an Enhancer RNA to Promote Medullary Thyroid Carcinoma Progression by Binding with FOXQ1.

BACKGROUND: Medullary thyroid carcinoma (MTC) is a rare but aggressive endocrine malignancy that originates from the parafollicular C cells of the thyroid gland. Enhancer RNAs (eRNAs) are non-coding RNAs transcribed from enhancer regions, which are critical regulators of tumorigenesis. However, the roles and regulatory mechanisms of eRNAs in MTC remain poorly understood. This study aims to identify key eRNAs regulating the malignant phenotype of MTC and to uncover transcription factors involved in the regulation of key eRNAs. METHODS: GSE32662 and GSE114068 were used for the identification of differentially expressed genes, eRNAs, enhancers and enhancer-regulated genes in MTC. Metascape and the transcription factor affinity prediction method were used for gene function enrichment and transcription factor prediction, respectively. qRT-PCR was used to detect gene transcription levels. ChIP-qPCR was used to assess the binding of histone H3 lysine 27 acetylation (H3K27ac)-enriched regions to anti- H3K27ac. RIP-qPCR was used to detect the binding between FOXQ1 and LINC00887. CCK8 and Transwell were performed to measure the proliferation and invasion of MTC cells, respectively. Intracellular reactive oxygen species (ROS) levels were quantified using a ROS assay kit. RESULTS: Four eRNAs (H1FX-AS1, LINC00887, MCM3AP-AS1 and A1BG-AS1) were screened, among which LINC00887 was the key eRNA promoting the proliferation and invasion of MTC cells. A total of 135 genes controlled by LINC00887-regulated enhancers were identified; among them, BCL2, PRDX1, SFTPD, TPO, GSS, RAD52, ZNF580, and ZFP36L1 were significantly enriched in the "ROS metabolic process" term. As a transcription factor regulating genes enriched in the "ROS metabolic process" term, FOXQ1 could recruit LINC00887. Overexpression of FOXQ1 restored LINC00887 knockdown-induced downregulation of GSS and ZFP36L1 transcription in MTC cells. Additionally, FOXQ1 overexpression counteracted the inhibitory effects of LINC00887 knockdown on the proliferation and invasion of MTC cells and the promotion of intracellular ROS accumulation induced by LINC00887 knockdown. CONCLUSION: LINC00887 was identified as a key eRNA promoting the malignant phenotype of MTC cells. The involvement of FOXQ1 was essential for LINC00887 to play a pro-tumorigenic role in MTC. Our findings suggest that the FOXQ1/LINC00887 axis is a potential therapeutic target for MTC.

dsRNAi-mediated silencing of PIAS2beta specifically kills anaplastic carcinomas by mitotic catastrophe.

The E3 SUMO ligase PIAS2 is expressed at high levels in differentiated papillary thyroid carcinomas but at low levels in anaplastic thyroid carcinomas (ATC), an undifferentiated cancer with high mortality. We show here that depletion of the PIAS2 beta isoform with a transcribed double-stranded RNA-directed RNA interference (PIAS2b-dsRNAi) specifically inhibits growth of ATC cell lines and patient primary cultures in vitro and of orthotopic patient-derived xenografts (oPDX) in vivo. Critically, PIAS2b-dsRNAi does not affect growth of normal or non-anaplastic thyroid tumor cultures (differentiated carcinoma, benign lesions) or cell lines. PIAS2b-dsRNAi also has an anti-cancer effect on other anaplastic human cancers (pancreas, lung, and gastric). Mechanistically, PIAS2b is required for proper mitotic spindle and centrosome assembly, and it is a dosage-sensitive protein in ATC. PIAS2b depletion promotes mitotic catastrophe at prophase. High-throughput proteomics reveals the proteasome (PSMC5) and spindle cytoskeleton (TUBB3) to be direct targets of PIAS2b SUMOylation at mitotic initiation. These results identify PIAS2b-dsRNAi as a promising therapy for ATC and other aggressive anaplastic carcinomas.

Transcriptomic characteristics according to tumor size and SUVmax in papillary thyroid cancer patients.

The SUVmax is a measure of FDG uptake and is related with tumor aggressiveness in thyroid cancer, however, its association with molecular pathways is unclear. Here, we investigated the relationship between SUVmax and gene expression profiles in 80 papillary thyroid cancer (PTC) patients. We conducted an analysis of DEGs and enriched pathways in relation to SUVmax and tumor size. SUVmax showed a positive correlation with tumor size and correlated with glucose metabolic process. The genes that indicate thyroid differentiation, such as SLC5A5 and TPO, were negatively correlated with SUVmax. Unsupervised analysis revealed that SUVmax positively correlated with DNA replication(r = 0.29, p = 0.009), pyrimidine metabolism(r = 0.50, p < 0.0001) and purine metabolism (r = 0.42, p = 0.0001). Based on subgroups analysis, we identified that PSG5, TFF3, SOX2, SL5A5, SLC5A7, HOXD10, FER1L6, and IFNA1 genes were found to be significantly associated with tumor aggressiveness. Both high SUVmax PTMC and macro-PTC are enriched in pathways of DNA replication and cell cycle, however, gene sets for purine metabolic pathways are enriched only in high SUVmax macro-PTC but not in high SUVmax PTMC. Our findings demonstrate the molecular characteristics of high SUVmax tumor and metabolism involved in tumor growth in differentiated thyroid cancer.

Identifying potential breath biomarkers for early diagnosis of papillary thyroid cancer based on solid-phase microextraction gas chromatography-high resolution mass spectrometry with metabolomics.

INTRODUCTION: Thyroid cancer incidence rate has increased substantially worldwide in recent years. Fine needle aspiration biopsy (FNAB) is currently the golden standard of thyroid cancer diagnosis, which however, is invasive and costly. In contrast, breath analysis is a non-invasive, safe and simple sampling method combined with a promising metabolomics approach, which is suitable for early cancer diagnosis in high volume population. OBJECTIVES: This study aims to achieve a more comprehensive and definitive exhaled breath metabolism profile in papillary thyroid cancer patients (PTCs). METHODS: We studied both end-tidal and mixed expiratory breath, solid-phase microextraction gas chromatography coupled with high resolution mass spectrometry (SPME-GC-HRMS) was used to analyze the breath samples. Multivariate combined univariate analysis was applied to identify potential breath biomarkers. RESULTS: The biomarkers identified in end-tidal and mixed expiratory breath mainly included alkanes, olefins, enols, enones, esters, aromatic compounds, and fluorine and chlorine containing organic compounds. The area under the curve (AUC) values of combined biomarkers were 0.974 (sensitivity: 96.1%, specificity: 90.2%) and 0.909 (sensitivity: 98.0%, specificity: 74.5%), respectively, for the end-tidal and mixed expiratory breath, indicating of reliability of the sampling and analysis method CONCLUSION: This work not only successfully established a standard metabolomic approach for early diagnosis of PTC, but also revealed the necessity of using both the two breath types for comprehensive analysis of the biomarkers.

In Silico Search for Drug Candidates Targeting the PAX8-PPARγ Fusion Protein in Thyroid Cancer.

The PAX8/PPARγ rearrangement, producing the PAX8-PPARγ fusion protein (PPFP), is thought to play an essential role in the oncogenesis of thyroid follicular tumors. To identify PPFP-targeted drug candidates and establish an early standard of care for thyroid tumors, we performed ensemble-docking-based compound screening. Specifically, we investigated the pocket structure that should be adopted to search for a promising ligand compound for the PPFP; the position of the ligand-binding pocket on the PPARγ side of the PPFP is similar to that of PPARγ; however, the shape is slightly different between them due to environmental factors. We developed a method for selecting a PPFP structure with a relevant pocket and high prediction accuracy for ligand binding. This method was validated using PPARγ, whose structure and activity values are known for many compounds. Then, we performed docking calculations to the PPFP for 97 drug or drug-like compounds registered in the DrugBank database with a thiazolidine backbone, which is one of the characteristics of ligands that bind well to PPARγ. Furthermore, the binding affinities of promising ligand candidates were estimated more reliably using the molecular mechanics Poisson-Boltzmann surface area method. Thus, we propose promising drug candidates for the PPFP with a thiazolidine backbone.

Promising Role of Alkaloids in the Prevention and Treatment of Thyroid Cancer and Autoimmune Thyroid Disease: A Comprehensive Review of the Current Evidence.

Thyroid cancer (TC) and thyroid autoimmune disorders (AITD) are among the most common diseases in the general population, with higher incidence in women. Chronic inflammation and autoimmunity play a pivotal role in carcinogenesis. Some studies, indeed, have pointed out the presence of AITD as a risk factor for TC, although this issue remains controversial. Prevention of autoimmune disease and cancer is the ultimate goal for clinicians and scientists, but it is not always feasible. Thus, new treatments, that overcome the current barriers to prevention and treatment of TC and AITD are needed. Alkaloids are secondary plant metabolites endowed with several biological activities including anticancer and immunomodulatory properties. In this perspective, alkaloids may represent a promising source of prophylactic and therapeutic agents for TC and AITD. This review encompasses the current published literature on alkaloids effects on TC and AITD, with a specific focus on the pathways involved in TC and AITD development and progression.

Cancer-associated fibroblast-derived periostin promotes papillary thyroid tumor growth through integrin-FAK-STAT3 signaling.

Background: Periostin (POSTN) is a critical extracellular matrix protein in various tumor microenvironments. However, the function of POSTN in thyroid cancer progression remains largely unknown. Methods: Postn and Rag1 knock-out mice and orthotopic mouse models were used to determine the role of POSTN on papillary thyroid tumor progression. Immunofluorescence, cell co-culture, fluorescence in situ hybridization, chromatin immunoprecipitation assay, recombinant protein and inhibitor treatment were performed to explore the underlying mechanisms of POSTN-promoted papillary thyroid tumor growth. Results: POSTN is up-regulated in papillary thyroid tumors and negatively correlates with the overall survival of patients with thyroid cancer. Cancer-associated fibroblast (CAF)-derived POSTN promotes papillary thyroid tumor growth in vivo and in vitro. POSTN deficiency in CAFs significantly impairs CAF-promoted papillary thyroid tumor growth. POSTN promotes papillary thyroid tumor cell proliferation and IL-4 expression through integrin-FAK-STAT3 signaling. In turn, tumor cell-derived IL-4 induces the activation of CAFs and stimulates POSTN expression by activating STAT6. We reveal the crucial role of CAF-derived POSTN and tumor cell-derived IL-4 in driving the development of papillary thyroid tumors through the POSTN-integrin-FAK-STAT3-IL-4 pathway in tumor cells and IL-4-STAT6-POSTN signaling in CAFs. Conclusion: Our findings underscore the significance of POSTN and IL-4 as critical molecular mediators in the dynamic interplay between CAFs and tumor cells, ultimately supporting the growth of papillary thyroid tumors.

Targeting NG2 relieves the resistance of BRAF-mutant thyroid cancer cells to BRAF inhibitors.

BRAFV600E represents a constitutively active onco-kinase and stands as the most prevalent genetic alteration in thyroid cancer. However, the clinical efficacy of small-molecule inhibitors targeting BRAFV600E is often limited by acquired resistance. Here, we find that nerve/glial antigen 2 (NG2), also known as chondroitin sulfate proteoglycan 4 (CSPG4), is up-regulated in thyroid cancers, and its expression is increased with tumor progression in a BRAFV600E-driven thyroid cancer mouse model. Functional studies show that NG2 knockout almost does not affect tumor growth, but significantly improves the response of BRAF-mutant thyroid cancer cells to BRAF inhibitor PLX4720. Mechanistically, the blockade of ERK-dependent feedback by BRAF inhibitor can activate receptor tyrosine kinase (RTK) signaling, causing the resistance to this inhibitor. NG2 knockout attenuates the PLX4720-mediated feedback activation of several RTKs, improving the sensitivity of BRAF-mutant thyroid cancer cells to this inhibitor. Based on this finding, we propose and demonstrate an alternative strategy for targeting NG2 to effectively treat BRAF-mutant thyroid cancers by combining multiple kinase inhibitor (MKI) Sorafenib or Lenvatinib with PLX4720. Thus, this study uncovers a new mechanism in which NG2 contributes to the resistance of BRAF-mutant thyroid cancer cells to BRAF inhibitor, and provides a promising therapeutic option for BRAF-mutant thyroid cancers.

Targeting miR-31 represses tumourigenesis and dedifferentiation of BRAFV600E-associated thyroid carcinoma.

BACKGROUND: BRAFV600E is the most common genetic mutation in differentiated thyroid cancer (DTC) occurring in 60% of patients and drives malignant tumour cell phenotypes including proliferation, metastasis and immune-escape. BRAFV600E-mutated papillary thyroid cancer (PTC) also displays greatly reduced expression of thyroid differentiation markers, thus tendency to radioactive iodine (RAI) refractory and poor prognosis. Therefore, understanding the molecular mechanisms and main oncogenic events underlying BRAFV600E will guide future therapy development. METHODS: Bioinformatics and clinical specimen analyses, genetic manipulation of BRAFV600E-induced PTC model, functional and mechanism exploration guided with transcriptomic screening, as well as systematic rescue experiments were applied to investigate miR-31 function within BRAFV600E-induced thyroid cancer development. Besides, nanoparticles carrying miR-31 antagomirs were testified to alleviate 131I iodide therapy on PTC models. RESULTS: We identify miR-31 as a significantly increased onco-miR in BRAFV600E-associated PTC that promotes tumour progression, metastasis and RAI refractoriness via sustained Wnt/ß-catenin signalling. Mechanistically, highly activated BRAF/MAPK pathway induces miR-31 expression via c-Jun-mediated transcriptional regulation across in vitro and transgenic mouse models. MiR-31 in turn facilitates ß-catenin stabilisation via directly repressing tumour suppressors CEBPA and DACH1, which direct the expression of multiple essential Wnt/ß-catenin pathway inhibitors. Genetic functional assays showed that thyroid-specific knockout of miR-31 inhibited BRAFV600E-induced PTC progression, and strikingly, enhanced expression of sodium-iodide symporter and other thyroid differentiation markers, thus promoted 131I uptake. Nanoparticle-mediated application of anti-miR-31 antagomirs markedly elevated radio-sensitivity of BRAFV600E-induced PTC tumours to 131I therapy, and efficiently suppressed tumour progression in the pre-clinical mouse model. CONCLUSIONS: Our findings elucidate a novel BRAF/MAPK-miR-31-Wnt/ß-catenin regulatory mechanism underlying clinically BRAFV600E-associated DTC tumourigenesis and dedifferentiation, also highlight a potential adjuvant therapeutic strategy for advanced DTC.

Therapeutic targeting of TNIK in papillary thyroid carcinoma: a novel approach for tumor growth suppression.

Papillary thyroid carcinoma (PTC) is a common endocrine malignancy. The pathology of PTC is far from clear. As a kinase that can be targeted, the role of TNIK in PTC has not been investigated. This study was focused on the effects and molecular mechanisms of TNIK in PTC. Both public datasets and clinical specimens were used to verify TNIK expression. The effects of TNIK were investigated in both cell lines and mice models. Transcriptome analysis was used to explore the underlying mechanism of TNIK. Immunofluorescence, wound healing, and qRT-PCR assays were used to validate the mechanism of TNIK in PTC. The therapeutic effects of TNIK inhibitor NCB-0846 were evaluated by flow cytometry, western blot, and subcutaneous xenografts mice. TNIK expression was upregulated in PTC tissues. TNIK knockdown could suppress cell proliferation and tumor growth in no matter cell models or nude mice. The transcriptome analysis, GO enrichment analysis, and GSEA analysis results indicated TNIK was highly correlated with cytoskeleton, cell motility, and Wnt pathways. The mechanistic studies demonstrated that TNIK regulated cytoskeleton remodeling and promoted cell migration. NCB-0846 significantly inhibited TNIK kinase activity, induced cell apoptosis, and activated apoptosis-related proteins in a dose-dependent manner. In addition, NCB-0846 inhibited tumor growth in tumor-bearing mice. In summary, we proposed a novel regulatory mechanism in which TNIK-mediated cytoskeleton remodeling and cell migration to regulate tumor progression in PTC. TNIK is a therapeutic target in PTC and NCB-0846 would act as a novel targeted drug for PTC therapy.

Homogentisic acid metabolism inhibits papillary thyroid carcinoma proliferation through ROS and p21-induced cell cycle arrest.

Thyroid cancer is one of the most common primary endocrine malignancies worldwide, and papillary thyroid carcinoma (PTC) is the predominant histological type observed therein. Although PTC has been studied extensively, our understanding of the altered metabolism and metabolic profile of PTC tumors is limited. We identified that the content of metabolite homogentisic acid (HGA) in PTC tissues was lower than that in adjacent non-cancerous tissues. We evaluated the potential of HGA as a novel molecular marker in the diagnosis of PTC tumors, as well as its ability to indicate the degree of malignancy. Studies have further shown that HGA contributes to reactive oxygen species (ROS) associated oxidative stress, leading to toxicity and inhibition of proliferation. In addition, HGA caused an increase in p21 expression levels in PTC cells and induced G1 arrest. Moreover, we found that the low HGA content in PTC tumors was due to the low expression levels of tyrosine aminotransferase (TAT) and p-hydroxyphenylpyruvate hydroxylase (HPD), which catalyze the conversion of tyrosine to HGA. The low expression levels of TAT and HPD are strongly associated with a higher probability of PTC tumor invasion and metastasis. Our study demonstrates that HGA could be used to diagnose PTC and provides mechanisms linking altered HGA levels to the biological behavior of PTC tumors.

Case report: A rare combination of aldosterone-secreting adrenocortical carcinoma and papillary thyroid carcinoma with Graves' disease.

Adrenocortical carcinoma (ACC) is a rare malignancy originating in the adrenal glands, aldosterone-producing ACC, even rarer. Papillary thyroid carcinoma (PTC), by contrast, accounts for the majority of thyroid carcinomas. We herein describe the first reported case of a female with comorbidities of aldosterone-producing ACC, PTC, and Graves' Disease(GD). The patient achieved transient clinical remission following adrenalectomy. However, three months later, aldosterone-producing ACC lung metastases emerged. Subsequently, within another three-month interval, she developed thyroid eye disease(TED). The patient died roughly one year after the adrenal operation. Exome sequencing did not reveal associations between aldosterone-producing ACC, PTC, and GD, and the underlying concurrence mechanism has yet to be elucidated. Further research of similar cases are needed to confirm potential links between the three pathologies.

Stimulated Raman Scattering Microscopy Reveals Aberrant Triglyceride Accumulation in Lymphatic Metastasis of Papillary Thyroid Carcinoma.

Lipid metabolic alterations are known to play a crucial role in cancer metastasis. As a key hub in lipid metabolism, intracellular neutral lipid accumulation in lipid droplets (LDs) has become a signature of aggressive human cancers. Nevertheless, it remains unclear whether lipid accumulation displays distinctive features in metastatic lesions compared to the primary ones. Here, we integrated multicolor stimulated Raman scattering (SRS) imaging with confocal Raman spectroscopy on the same platform to quantitatively analyze the amount and composition of LDs in intact human thyroid tissues in situ without any processing or labeling. Inspiringly, we found aberrant accumulation of triglycerides (TGs) in lymphatic metastases but not in normal thyroid, primary papillary thyroid carcinoma (PTC), or normal lymph node. In addition, the unsaturation degree of unsaturated TGs was significantly higher in the lymphatic metastases from patients diagnosed with late-stage (T3/T4) PTC compared to those of patients diagnosed with early-stage (T1/T2) PTC. Furthermore, both public sequencing data analysis and our RNA-seq transcriptomic experiment showed significantly higher expression of alcohol dehydrogenase-1B (ADH1B), which is critical to lipid uptake and transport, in lymphatic metastases relative to the primary ones. In summary, these findings unravel the lipid accumulation as a novel marker and therapeutic target for PTC lymphatic metastasis that has a poor response to the regular radioactive iodine therapy.

Dihydrotanshinone I exhibits antitumor effects via ß-catenin downregulation in papillary thyroid cancer cell lines.

Thyroid cancer is the most common endocrine carcinoma and, among its different subtypes, the papillary subtype (PTC) is the most frequent. Generally, PTCs are well differentiated, but a minor percentage of PTCs are characterized by a worse prognosis and more aggressive behavior. Phytochemicals, naturally found in plant products, represent a heterogeneous group of bioactive compounds that can interfere with cell proliferation and the regulation of the cell cycle, taking part in multiple signaling pathways that are often disrupted in tumor initiation, proliferation, and progression. In this work, we focused on 15,16-dihydrotanshinone I (DHT), a tanshinone isolated from Salvia miltiorrhiza Bunge (Danshen). We first evaluated DHT biological effect on PTC cells regarding cell viability, colony formation ability, and migration capacity. All of these parameters were downregulated by DHT treatment. We then investigated gene expression changes after DHT treatment by performing RNA-seq. The analysis revealed that DHT significantly reduced the Wnt signaling pathway, which plays a role in various diseases, including cancer. Finally, we demonstrate that DHT treatment decreases protein levels of ß-catenin, a final effector of canonical Wnt signaling pathway. Overall, our data suggest a possible use of this nutraceutical as an adjuvant in the treatment of aggressive papillary thyroid carcinoma.

CircPHGDH downregulation decreases papillary thyroid cancer progression through miR-122-5p/PKM2 axis.

BACKGROUND: Although papillary thyroid carcinoma (PTC) has a favorable prognosis, it could affect patient life quality and become a serious threat because of invasion and metastasis. Many investigations have suggested that circular RNAs (circRNAs) are involved in different cancer regulations. Nevertheless, circRNAs role in invasive PTC remains unclear. METHODS: In the present investigation, next-generation sequencing was applied to explore abnormal circRNA expression. The expression of circRNA phosphoglycerate dehydrogenase (circPHGDH) in PTC cell lines and tissues were examined. Then, we investigated regulatory mechanism and circPHGDH downstream targets using bioinformatics analysis and luciferase reporting analysis. Then transwell migration, Cell Counting Kit-8 (CCK8) and 5-ethynyl-2'-deoxyuridine (EdU) assays were used for cells migration and proliferation analysis. In vivo metastasis and tumorigenesis assays were also employed to evaluate the circPHGDH role in PTC. RESULTS: The data showcased that circPHGDH expression increased in both PTC cell lines and tissues, which suggested that circPHGDH functions in PTC progression. circPHGDH downregulation suppressed PTC invasion and proliferation in both in vivo and in vitro experiments. Bioinformatics and luciferase reporter results confirmed that both microRNA (miR)-122-5p and pyruvate kinase M2 subtype (PKM2) were downstream targets of circPHGDH. PKM2 overexpression or miR-122-5p suppression reversed PTC cell invasion and proliferation post silencing circPHGDH by restoring aerobic glycolysis. CONCLUSION: Taken together, our research found that circPHGDH downregulation reduced PTC progression via miR-122-5p/PKM2 axis regulation mediated by aerobic glycolysis.

Antitumor activity of extracellular signal-regulated kinases 1/2 inhibitor BVD-523 (ulixertinib) on thyroid cancer cells.

OBJECTIVE: This study aimed to investigate BVD-523 (ulixertinib), an adenosine triphosphate (ATP)-dependent extracellular signal-regulated kinases 1/2 inhibitor, for its antitumor potential in thyroid cancer. MATERIALS AND METHODS: Ten thyroid cancer cell lines known to carry mitogen-activated protein kinase (MAPK)-activated mutations, including v-Raf murine sarcoma viral oncogene homolog B (BRAF) and rat sarcoma virus (RAS) mutations, were examined. Cells were exposed to a 10-fold concentration gradient ranging from 0 to 3000 nM for 5 days. The half-inhibitory concentration was determined using the Cell Counting Kit-8 assay. Following BVD-523 treatment, cell cycle analysis was conducted using flow cytometry. In addition, the impact of BVD-523 on extracellular signal-regulated kinase (ERK)- dependent ribosomal S6 kinase (RSK) activation and the expression of cell cycle markers were assessed through western blot analysis. RESULTS: BVD-523 significantly inhibited thyroid cancer cell proliferation and induced G1/S cell cycle arrest dose-dependently. Notably, cell lines carrying MAPK mutations, especially those with the BRAF V600E mutation, exhibited heightened sensitivity to BVD-523's antitumor effects. Furthermore, BVD-523 suppressed cyclin D1 and phosphorylated retinoblastoma protein expression, and it robustly increased p27 levels in an RSK-independent manner. CONCLUSION: This study reveals the potent antitumor activity of BVD-523 against thyroid cancer cells bearing MAPK-activating mutations, offering promise for treating aggressive forms of thyroid cancer.

VDR is a potential prognostic biomarker and positively correlated with immune infiltration: a comprehensive pan-cancer analysis with experimental verification.

The vitamin D receptor (VDR) is a transcription factor that mediates a variety of biological functions of 1,25-dihydroxyvitamin D3. Although there is growing evidence of cytological and animal studies supporting the suppressive role of VDR in cancers, the conclusion is still controversial in human cancers and no systematic pan-cancer analysis of VDR is available. We explored the relationships between VDR expression and prognosis, immune infiltration, tumor microenvironment, or gene set enrichment analysis (GSEA) in 33 types of human cancers based on multiple public databases and R software. Meanwhile, the expression and role of VDR were experimentally validated in papillary thyroid cancer (PTC). VDR expression decreased in 8 types and increased in 12 types of cancer compared with normal tissues. Increased expression of VDR was associated with either good or poor prognosis in 13 cancer types. VDR expression was positively correlated with the infiltration of cancer-associated fibroblasts, macrophages, or neutrophils in 20, 12, and 10 cancer types respectively and this correlation was experimentally validated in PTC. Increased VDR expression was associated with increased percentage of stromal or immune components in tumor microenvironment (TME) in 24 cancer types. VDR positively and negatively correlated genes were enriched in immune cell function and energy metabolism pathways, respectively, in the top 9 highly lethal tumors. Additionally, VDR expression was increased in PTC and inhibited cell proliferation and migration. In conclusion, VDR is a potential prognostic biomarker and positively correlated with immune infiltration as well as stromal or immune components in TME in multiple human cancers.